When system pressure exceeds 100 psi, what is the maximum unsupported distance between the end sprinkler in the pendant position and the closest hanger?

When the system pressure exceeds 100 psi, the maximum unsupported distance between the end sprinkler in the pendant position and the closest hanger is dictated by the material of the pipe used in the fire sprinkler system. For steel piping, the industry standard allows for a maximum unsupported distance of 1 foot. This is due to the strength and rigidity of the steel, which can support a greater span without sagging or compromising the system.

On the other hand, softer materials like copper and CPVC have a maximum unsupported distance of 6 inches. This limitation is in place because these materials are more flexible and can be affected by temperature changes as well as the pressure of the water flowing within them. If the distances exceed these standards, it can lead to potential issues such as sagging, misalignment, or even pipe failure, which can significantly compromise the effectiveness of the fire protection system.

Therefore, option B accurately reflects the proper unsupported distances based on the different materials used, ensuring that the integrity and functionality of the sprinkler system are maintained when system pressures are high.